Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

AUO4 and A3UO6 uranates (A=Ca, Sr, Ba or Pb) have been synthesized by solid-state reaction. Their crystallographic struc-tures have been studied combining Powder X-ray Diffraction (PXRD) and Extended X-ray Absorption Fine Structure (EXAFS). To our knowledge, this is the first time the local environment of these uranates have been investigated by EXAFS. Depending on the nature of the alkali earth metal, the uranates compounds crystallize in different structures, in which the uranium local environment around the atoms have been identified. The U geometry is then compared to the oxidation states determined from X-ray Absorption Near Edge Spectroscopy (XANES).